#include<iostream>
#include<string>

using namespace std;

int is_upper( string const &s){
    int flag = 0;
    for (auto i : s){
        if(isupper(i)){
            ++flag;
        }
    }
    return((flag == 0) ? 0 :1);
}

void to_lower(string &s){
    for (auto &i : s){
        i = tolower(i);
    }
}

int main(){
    string str;
    cout << "请输入一个单词！"<<endl;
    cin >> str;
    if(is_upper(str)) to_lower(str);
    cout << "单词小写化:" << " ";
    for (auto s : str){
        cout << s;
    }
    cout << endl;
    return 0;
}